Compositions and techniques for delivering hydrophobic skin benefit agents to the skin are reported in the prior art. The usual skin benefit agents are fatty or oleaginous materials such as emollient oils, e.g., sunflower oil, mineral oil, coconut oil, soybean oil, almond oil, corn oil and oils from nuts or seeds; or oleaginous, emollient organic materials, e.g., fatty acids, fatty acid salts, fatty alcohols and fatty acid esters, e.g., isopropyl myristate. Transfer of the skin benefit agents to the skin is accomplished in the course of using the product. Products generally fall into three classes—leave on products, products that are applied to and removed from the skin and detergent products containing emollient fatty matter emulsified therein dispersed in water used to wash the skin.
Further, it is known to prepare cosmetic or dermatological compositions containing the skin benefit agents in the form of emulsions or creams. The emulsions may be of the oil-in-water type or the water-in-oil type and normally consist of two immiscible phases and a surfactant whose role is to stabilize one phase in the other phase. In cream form, the ultimate product may be in emulsion form or in suspension form wherein a thickener in the form a powder is employed. However, whether in the form of an emulsion, suspension or cream, the ultimate stability at various temperatures in the range of 5° C. to 50° C. may be a problem. Also, in use, the user may experience a more or less an unpleasant greasy effect or tacky effect depending upon the oil or emollient material employed or the emulsifier/thickener material employed or the overall formulation selected. In addition, the emulsifier/thickener whose presence is necessary for stability can prove to be an irritant to the skin. These prior art products are described in chapters 4-6 in “Cosmetics, Science and Technology” edited by Edward Sagarin, copyright 1957.
Further, exfoliating compositions also are well known in the art and typically remove dirt, residual make up and dead skin cells by abrasion produced by a wide variety of particulate materials in a variety of states of comminution. Typically, the particulate matter is suspended in the compositions. Again, a vast number of materials of widely varying particle sizes and chemical identities have been used as exfoliating particles. Illustrative of particulate materials that have been used heretofore are the well known mineral-based materials such as aluminum oxide, synthetic alumina, volcanic ash, diatomaceous earth, bentonite, talc, pumice and silica. Other particulate materials that have been employed are powders of organic polymers, namely, polyethylene, polypropylene, polystyrene, organopolysiloxane, nylon, polyvinyl chloride and cellulose as well as co-polymers of acrylonitrile, acrylate, vinylidene chloride and styrene based monomers. Other particulate materials include powders obtained from the apricot, almond, birch, walnut, peach, sunflower and watermelon seeds and powders of inorganic salts such as calcium carbonate, dicalcium phosphate, sodium metaphosphate, zeolite and sodium chloride. As stated above, the foregoing particulate materials have been utilized in a variety of particle sizes, with the small particle sizes being favored because of the emphasis on particles that do not feel gritty. In any event, by integrating the amount of particulate material and the particle size thereof and the fatty vehicle in which the particles are dispersed, a large number of the foregoing particulate materials can be employed in exfoliating compositions that are suitable for use on the skin. Again, the problems encountered with the exfoliating compositions are temperature stability of the product and the effectiveness of the product in use, e.g., deposits a desirable film of fatty matter on the skin while smoothing and softening the skin.
In view of the foregoing discussion, it appears that there still is a need for stable compositions containing emollient material in the form of an extrudable paste or cream that are suitable for cleansing the skin and depositing a film of emollient material on the skin such that the skin has a non-greasy after-feel when the composition is applied to and massaged into the skin, rinsed off the skin with clear, tepid water and the skin is dried. In addition, a need exists for stable, skin exfoliating compositions in the form of a temperature stable, extrudable paste or cream that are suitable for cleansing and conditioning the skin with fatty matter when employed in the method set forth above.
Furthermore, with respect to the skin exfoliating compositions containing particulate matter, it appears that commercial use of water-soluble salts, e.g., sodium chloride, in particulate form in compositions for exfoliating the skin is almost non-existent. For example, the effectiveness of sodium chloride as a skin exfoliant is well known and this material is readily available and economically attractive. Further, from an environmental standpoint sodium chloride is safe and not harmful to the environment. Also, it is water soluble and easily removed from the skin. It seems that the problem associated with the use of sodium chloride in cosmetic compositions for exfoliating the skin is the problem of forming a stable suspension. Where sodium chloride is used as the particulate exfoliating agent, normally it is admixed with the remainder of the exfoliating skin composition just prior to use or the ingredients of the exfoliating composition are applied to skin sequentially without prior mixing. In fact, U.S. Pat. No. 5,360,824 discloses in Example I an exfoliating composition containing sodium chloride that is prepared just prior to use, because that composition separates at 24° C. and at 50° C. within one hour of manufacture.
In conclusion, it appears that a need still exists for a topical skin composition that will cleanse surface grime and oil from the skin and leave a deposit of a thin film of emollient material on the skin which is effective to soften, smooth and moisturize the treated skin without a greasy after-feel when the composition is removed from the skin by rinsing it with tepid water and the skin is dried.